They were named as Laurent Sbasnik, Lucie Mei-Dalby, Volodia Guinard, Brice Guilbert and Edouard Gilles.

The Argentine pilots were named as Juan Carlos Castillo and Roberto Abate.

Other contestants were standing on the ground blindfolded a few hundred metres away when the accident happened, French media said.

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The three dead stars are visible on the right-hand side of this image of the athletes leaving for Argentina. It was uploaded to Facebook by French Olympian Philippe Candeloro (middle left)

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The three sport stars who died were pictured moments before boarding the helicopter

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The accident happened in the remote, rugged province of La Rioja, close to the Andes mountains

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The collision took place moments after the helicopters had taken off

French prosecutors have opened an inquiry into the deaths - standard procedure when nationals die overseas.

Meanwhile Culture Minister Fleur Pellerin told the BFM-TV news channel that the three athletes were "among the most outstanding ambassadors for our country".

Former Arsenal and France striker Sylvain Wiltord, who was taking part in the current series, said via social media, "I'm trembling, I can't talk. I'm horrified." And a former team-mate of Camille Muffat, Yannick Agnel said simply: "not her… Let us be strong."

But amid the horror there are also the first signs of anger. Well-known musician Benjamin Bioley has criticised what he called a "horrible TV reality show that serves up cardboard stars and then steals three wonderful athletes".

As the country begins to absorb the news, the questions over this incident and the circumstances that led to it will only grow.

Filming had begun late last month at Ushuaia in the deep south of Argentina and had since moved to the mountainous western province of Rioja.

One cast member, figure skater Philippe Candeloro, was said to be "extremely shocked but unharmed".

Officials have said the weather conditions in the mountainous area where the helicopters went down were good.

"An explosion occurred and it's believed that they must have collided,'' said La Rioja Secretary of Security Cesar Angulo.

"Aeronautical experts will have to determine that," he added.

"We learn with great sadness about the accident during the filming of the Dropped show," said a statement issued by TF1.

"All TF1 teams come together in this terrible time with the pain of the families and relatives of the victims."

TF1 says the show will be postponed and the rest of the crew is returning home.

Reality TV meets tragedy

2013: On Koh Lanta show produced by ALP for TF1, Gerald Babin, 25, dies of a heart attack. Days later the doctor who treated him, Thierry Costa, 38, kills himself complaining of bad media coverage

2010: Phil Harris, a fisherman, suffers a huge stroke while unloading crab during filming for Discovery Channel's Deadliest Catch reality series and dies days later. The episode featuring his death is later broadcast, followed by a special tribute episode

2009: a contestant on the Bulgarian version of Survivor, Noncho Vodenicharov, 53, suffers a heart attack in the Philippines and dies

2009: Saad Khan, a 32-year-old father of four, drowns while taking part in a swimming challenge on a Pakistani reality TV show

2006: Australian Steve Irwin, international wildlife expert and star, dies off Queensland coast after being pierced with a stingray barb while shooting a film called Ocean's Deadliest